The invention relates to pharmaceutical compositions in the form of tablets which contain cefixime and for a process of making the same.
In particular, this invention relates to a drug delivery system for delivering cefexime.
Cefixime is hygroscopic, slightly soluble in water; sparingly soluble in dehydrated alcohol; practically insoluble in ethyl acetate; freely soluble in methyl alcohol. A 5% suspension in water has a pH of 2.6 to 4.1.
Cefixime is a cephalosporin antibiotic, which can be administered orally and resembles, in respect of its structure, the spectrum of organisms and the beta-lactamase stability, the 3rd generation cephalosporins of the cefotaxime type, which can be administered parent rally. The introduction of an acid substituent into the 7.beta.-side chain of aminothiazolyl-cephalosporins, as, for example, in cefixime, leads to a compound, which can be absorbed enterally.
Like all representatives of this class of substances, it has a bactericidal action. The mechanism of action of cefixime is based on inhibition of bacterial cell wall synthesis. The acute toxicity of cefixime is negligibly low. Cefixime is stable to hydrolysis by many beta-lactamases. It has a mode of action and spectrum of activity similar to that of the third-generation cephalosporin cefotaxime but some Enterobacteriaceae are less susceptible to cefixime. Haemophilus influenzae, Moraxella (Branhamella) catarrhalis, and Neisseria gonorrhoeae are sensitive, including penicillinase-producing strains. Of the Gram-positive bacteria, streptococci are sensitive to cefixime but most strains of staphylococci, enterococci, and Listeria spp. are not.
Only 40 to 50% of an oral dose of cefixime is absorbed from the gastrointestinal tract, whether taken before or after meals, although the rate of absorption may be decreased in the presence of food. Conventionally, cefixime is better absorbed from oral suspension than from tablets. Absorption is fairly slow. Peak plasma concentrations of 2 to 3 micrograms per mL and 3.7 to 4.6 micrograms per mL have been reported between 2 and 6 hours after single doses of 200 and 400 mg, respectively. The plasma half-life is usually about 3 to 4 hours and may be prolonged when there is renal impairment. About 65% of cefixime in the circulation is bound to plasma proteins. Information on the distribution of cefixime in body tissues and fluids is limited. It crosses the placenta. Relatively high concentrations may be achieved in bile and urine. About 20% of an oral dose (or 50% of an absorbed dose) is excreted unchanged in the urine within 24 hours. Up to 60% may be eliminated by nonrenal mechanisms; there is no evidence of metabolism but some is probably excreted into the faeces from bile. It is not substantially removed by dialysis.
Cefixime is suitable for the treatment of acute and chronic infections of varying severity caused by cefixime-sensitive pathogens and amenable to oral therapy.
Cefixime has bactericidal effects and is effective, for example, for the following pathogens: Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae; Hamophilus influenzae, Neisseria gonorrhoeae, Escherichia coli, Proteus mirabilis, Proteus vulgaris, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter sp., Pasteurella multocida, Providencia sp., Salmonella sp., Shigella sp., Citrobacter amalonaticus, Citrobacter diversus, Serratia marcescens. 
Cefixime-containing compositions are used only in the form of solid dosage forms such as tablets, capsules, granules or powders.